This invention is directed to a control mechanism for a cyclically operable electric motor assembly which can be used to control a helical feed of a vending machine.
The present invention is disclosed principally in connection with small (sub-fractional horsepower) direct current electric motors used in vending machines and which are controlled by a microprocessor although the invention may be applied equally well to other purposes where the principle is applicable.
Certain kinds of vending machines employ one or more small electric motors to control delivery of the products sold by the machines. In one form of vending machine, packaged products are delivered by what amounts to a large helical (spring) feeder mounted on a shaft driven by a small electric motor. Previously, the electric motors were of the alternating current type powered by 110 volts alternating current. These motors are now being replaced by low voltage direct current electric motors which may be more easily controlled by a microprocessor.
When proper coinage is inserted in the vending machine, a circuit for the microprocessor is actuated to energize the motor. The motor remains energized until the helical feeder has delivered the product. When the delivery is complete, the motor is stopped by shorting the circuit for the microprocessor.
These vending machine motors are small and usually include a gear train for speed reduction with the gear train located in a housing. As previously constructed, the alternating current motors had gear trains in metal housings. A microswitch was fastened to the metal housing by screws and a metal pawl was operatively connected between the output gear of the gear train and the microswitch in order to operate the microswitch at the beginning and end of each revolution of the output gear. This construction required expensive parts and was costly and time consuming to assemble.
Therefore, it is an object of this invention to provide a control mechanism for an electric motor assembly in which the switch mechanism for completing and interrupting the microprocessor can be integrally mounted on the gear housing by heat staking the switch block to the gear housing.
Another object is to reduce the cost of construction of small electric motor assemblies by forming the quick connect terminals integrally with the switch contact blades.
Another object of this invention is a switch mechanism having contact blades which employ cross point contacts with a large amount of wiping action.
Other objects may be found in the following specification, claims and drawings.